• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1997년도 춘계학술발표회 논문집
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• pp.190-192
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• 1997

• 한국고분자학회지:고분자과학과기술
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• 제23권5호
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• pp.541-546
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• 2012

• Macromolecular Research
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• 제10권1호
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• pp.2-12
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• 2002

The small-angle X-ray scattering (SAXS) beamline BL4C1 at the 2.5 GeV storage ring of the Pohang Accelerator Laboratory (PAL) has been in its first you of operation since August 2000. During this first stage it could meet the basic requirements of the rapidly growing domestic SAXS user community, which has been carrying out measurements mainly on various polymer systems. The X-ray source is a bending magnet which produces white radiation with a critical energy of 5.5 keV. A synthetic double multilayer monochromator selects quasi-monochromatic radiation with a bandwidth of ca. 1.5%. This relatively low degree of monochromatization is sufficient for most SAXS measurements and allows a considerably higher flux at the sample as compared to monochromators using single crystals. Higher harmonics from the monochromator are rejected by reflection from a flat mirror, and a slit system is installed for collimation. A charge-coupled device (CCD) system, two one-dimensional photodiode arrays (PDA) and imaging plates (IP) are available its detectors. The overall performance of the beamline optics and of the detector systems has been checked using various standard samples. While the CCD and PDA detectors are well-suited for diffraction measurements, they give unsatisfactory data from weakly scattering samples, due to their high intrinsic noise. By using the IP system smooth scattering curves could be obtained in a wide dynamic range. In the second stage, stating from August 2001, the beamline will be upgraded with additional slits, focusing optics and gas-filled proportional detectors.

• Macromolecular Research
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• 제8권3호
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• pp.103-115
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• 2000

The structural changes viewed from the molecular level have been investigated for the isothermal crystallization phenomena of polyethylene (PE) and the solvent-induced crystallization phenomenon of syndiotactic polystyrene (sPS) glassy sample. The data, which were collected by the time-resolved measurements of Fourier-transform infrared spectra, Raman spectra, synchrotron-sourced small-angle X-ray scattering, wide-angle X-ray scattering, and so on, were combined together to extract the detailed structural information in these phase transition phenomena. In the case of PE, the isothermal crystallization from the melt to the orthorhombic form was found to occur via the conformationally-disordered trans chain form, followed by the formation of the lamellar stacking structure of regular orthorhombic-type crystals. In the case of sPS, the amorphous chains in the glassy sample were found to enhance the mobility through the interaction with the injected solvent molecules, which act as a trigger to cause the conformational ordering from the random coil to the regular T$_2$G$_2$-type helical form. The thus created short helical segments were found to grow into longer helices, which gathered together to form the crystallites, as revealed by the organized coupling of the infrared, Raman and X-ray scattering data.

• 한국고분자학회지:고분자과학과기술
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• 제21권4호
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• pp.336-344
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• 2010

• 한국결정학회지
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• 제4권1호
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• pp.36-41
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• 1993

BaTi-에톡사이드로 부터 유도된 솔의 옥소폴리머에 대하여 저각 X선 산란을 이용하여 조사하였다. NH, OH를 사용하거나 혹은 촉매제가 없이 얻어진 솔에서 옥소폴리머 구조의 성장은 비슷하다. 이 솔들의 선회반경은 1.66-2.08nm이다. 이들은 차원 값이 1.6인 질량 프락탈의 거동을 따르며 이 거동은 NH40H 첨가량에 는 거의 무관하다. CHSCOOH를 촉매로 사용하여 얻은 솔의 선회반경은 2.87-3.67nm로서 염기성 촉매 혹은 촉매없이 얻은 솔에 비해 보다 큰 값을 가진다 이들 솔의 산란곡선은 중간 Q 영역에서 비슷하며 프락탈 차원은 1.8이다. 염기성 혹은 중성 수화조건으로 부터 얻 은 솔의 윽소폴리머는 짧은 사슬형 구조를 가질 것이나 산성 수화조건에서는 이들은 보다 분기되고 길어지는 사슬형으로 성장되는 경향을 가진다.

• Elastomers and Composites
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• 제54권2호
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• pp.156-160
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• 2019

The changes in the dispersion of carbon black in liquid polyisoprene under shear flow with time have been investigated by time-resolved ultra small-angle X-ray scattering (USAXS) method. The analyses of USAXS profile immediately after the start of shear flow clarified that the aggregates of carbon black with a mean radius of gyration of 14 nm and surface fractal dimension of 2.5 form the fractal network structure with mass-fractal dimension of 2.9. After the application of the shear flow, the scattering intensity increases with time at the observed whole entire q region, and then the a shoulder appears at $q=0.005nm^{-1}$, indicating that the agglomerate is broken and becomes smaller by shear flow. The analysis by the Unified Guinier/Power-law approach yielded several characteristic parameters, such as the sizes of aggregate and agglomerate, mass-fractal dimension of agglomerate, and surface fractal dimension of the primary particle. While the mean radius of gyration of the agglomerate decreases with time, the mean radius of gyration of the aggregate, mass fractal dimension, and surface fractal dimension don't change with time, indicating that the aggregates peel off the surface of the agglomerate.

• 폴리머
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• 제33권2호
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• pp.183-188
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• 2009

일축인장에 의하여 변형핀 1-옥텐 공단량체를 함유하는 폴리에틸렌과 고밀도 폴리에틸렌을 대상으로 이들의 온도 상승에 따른 구조 이완 거동을 방사광 가속기를 이용한 실시간 광각 및 소각 X-선 산란법으로 연구하였다. 일축 변형된 폴리에틸렌은 온도가 상승함에 따라 결정의 전이, 부서진 라멜라의 재배열 등 구조적 변화거동이 수반 되었으며 이는 공단량체의 합량에 따라 매우 다르게 나타났다. 공단량체 함량이 2 wt% 이하인 폴리에틸렌의 경우 일축 변형 과정에서 마르텐사이트 전이에 의해 생성된 monoclinic 격자가 온도 상승에 따라 orthorhombic 결정격자로 재전이되고 부서진 라멜라간 재배열 거동을 보였으나 9.5 wt%의 고함량에서는 라멜라의 재배열 거동이 관찰되지 않았으며 결정 격자의 전이 거동도 관찰되지 않았다.

• Macromolecular Research
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• 제14권1호
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• pp.45-51
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• 2006

We conducted simultaneous, small-angle, X-ray scattering/differential scanning calorimetry (SAXS/DSC) and simultaneous, wide-angle, X-ray scattering (WAXS)/DSC measurements for a polymer blend of poly($\varepsilon$-caprolactone)/poly(ethylene glycol)(PCL/PEG). The time-dependent SAXS/DSC and WAXS/DSC results, measured while the system was quenched below the melting temperature of PCL from a melting state, revealed the competitive behavior between liquid-liquid phase separation and crystallization in the polymer blend. The time-dependent structural evolution extracted from the SAXS/WAXS/DSC results can be characterized by the following four stages in the PCL crystallization process: the induction (I), nucleation (II), growth (III), and late (IV) stages. The influence of the liquid-liquid phase separation on the crystallization of PCL was also observed by phase-contrast microscope and polarized microscope with 1/4$\lambda$ compensator.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1485-1489
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• 2003

The gelation for di-(2-ethylhexyl) phthalate (DEHP)-plasticized poly(vinyl chloride) was studied by measuring time-resolved small-angle X-ray scattering (SAXS) and a flow of the solutions in test tube. It was found that for the gelation there were three regimes. At Regime I, the solution rapidly changed to a gel, and the SAXS intensity showed a peak and the peak intensity increased, keeping the peak angle constant. Applying the SAXS intensity to the kinetic analysis of the liquid-liquid phase separation, it was revealed that the spinodal decomposition proceeded to develop a periodic length of 29.9 nanometer in size, a hydrogen-bonding-type association in polymer rich phase followed, and then it induced fast gelation rate. At Regime II, the gelation slowly occurred and the SAXS intensity was not observed, suggesting that a homogeneous gel network was formed by a hydrogen-bonding. At regime III, the solution was a homogeneous sol.